pr-preview.yml

name: PR Preview

on:
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review]

permissions:
  contents: read
  issues: write
  pull-requests: write

concurrency:
  group: pr-preview-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  deploy-cloudflare-preview:
    runs-on: ubuntu-latest
    if: ${{ !github.event.pull_request.head.repo.fork && vars.CLOUDFLARE_PAGES_PROJECT != '' && vars.CLOUDFLARE_ACCOUNT_ID != '' }}
    permissions:
      contents: read
      deployments: write
    outputs:
      preview_url: ${{ steps.cf.outputs.pages-deployment-alias-url }}
      deployment_url: ${{ steps.cf.outputs.deployment-url }}
      has_token: ${{ steps.token_check.outputs.has_token }}
    steps:
      - name: Check Cloudflare token
        id: token_check
        env:
          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
        run: |
          if [ -n "$CLOUDFLARE_API_TOKEN" ]; then
            echo "has_token=true" >> "$GITHUB_OUTPUT"
          else
            echo "has_token=false" >> "$GITHUB_OUTPUT"
          fi

      - name: Checkout
        if: ${{ steps.token_check.outputs.has_token == 'true' }}
        uses: actions/checkout@v6

      - name: Set up Ruby
        if: ${{ steps.token_check.outputs.has_token == 'true' }}
        uses: ruby/setup-ruby@v1
        with:
          ruby-version: "3.1"
          bundler-cache: true

      - name: Build site
        if: ${{ steps.token_check.outputs.has_token == 'true' }}
        run: bundle exec jekyll build

      - name: Publish to Cloudflare Pages
        id: cf
        if: ${{ steps.token_check.outputs.has_token == 'true' }}
        uses: cloudflare/wrangler-action@v3
        with:
          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
          accountId: ${{ vars.CLOUDFLARE_ACCOUNT_ID }}
          command: pages deploy _site --project-name=${{ vars.CLOUDFLARE_PAGES_PROJECT }} --branch=pr-${{ github.event.number }}
          gitHubToken: ${{ secrets.GITHUB_TOKEN }}
          wranglerVersion: "3"

  comment-preview:
    runs-on: ubuntu-latest
    needs: deploy-cloudflare-preview
    if: ${{ always() && !github.event.pull_request.head.repo.fork && (needs.deploy-cloudflare-preview.result == 'success' || needs.deploy-cloudflare-preview.result == 'skipped' || needs.deploy-cloudflare-preview.result == 'failure') }}
    steps:
      - name: Add or update PR preview comment
        uses: actions/github-script@v7
        env:
          RUN_URL: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}
          CLOUDFLARE_URL: ${{ needs.deploy-cloudflare-preview.outputs.preview_url }}
          CLOUDFLARE_DEPLOYMENT_URL: ${{ needs.deploy-cloudflare-preview.outputs.deployment_url }}
          CLOUDFLARE_ENABLED: ${{ vars.CLOUDFLARE_PAGES_PROJECT != '' && vars.CLOUDFLARE_ACCOUNT_ID != '' && needs.deploy-cloudflare-preview.outputs.has_token == 'true' }}
          CLOUDFLARE_RESULT: ${{ needs.deploy-cloudflare-preview.result }}
        with:
          script: |
            const marker = "<!-- pr-preview-comment -->";
            const previewUrl = process.env.CLOUDFLARE_URL || process.env.CLOUDFLARE_DEPLOYMENT_URL;

            const cloudflareLine = process.env.CLOUDFLARE_ENABLED === "true"
              ? (process.env.CLOUDFLARE_RESULT === "success"
                ? (previewUrl
                  ? `- Hosted preview (Cloudflare Pages): [Open preview](${previewUrl})`
                  : "- Hosted preview (Cloudflare Pages): deployed, but URL output was empty. Check deployment details.")
                : `- Hosted preview (Cloudflare Pages): deployment did not succeed; check [workflow logs](${process.env.RUN_URL}).`)
              : "- Hosted preview (Cloudflare Pages): not configured (set repository vars/secrets; see README).";

            const body = `${marker}
            ## PR Preview Ready

            ${cloudflareLine}
            `;

            const { owner, repo } = context.repo;
            const issue_number = context.issue.number;
            const comments = await github.rest.issues.listComments({
              owner,
              repo,
              issue_number,
              per_page: 100,
            });

            const existing = comments.data.find((comment) => comment.body && comment.body.includes(marker));
            if (existing) {
              await github.rest.issues.updateComment({
                owner,
                repo,
                comment_id: existing.id,
                body,
              });
            } else {
              await github.rest.issues.createComment({
                owner,
                repo,
                issue_number,
                body,
              });
            }